The invention relates to an electron tube comprising a tubular glass envelope portion having a central axis and an inside diameter D, and an electrode system inserted into the tubular envelope portion and having a central axis which coincides at least substantially with the central axis of the tubular envelope portion. The electrode system comprises a number of resilient elements, which extend towards the wall of the envelope portion and at their free ends each press against a respective inwardly protruding wall portion, of the tubular envelope portion, which has a distance R.sub.1 to the central axis, R.sub.1 being &lt;D/2.
Such an electron tube is known from U.S. Pat. No. 2,171,766. In this Specification a cathode ray tube is described in which the resilient elements, in addition to a centering action, also fix the position of the electrode system in the axial direction. For that purpose the tube neck comprises an internal protuberance which cooperates with an aperture or indentation in the free end of a resilient element, so that a snap connection is formed. When the electrode system is inserted into the tube neck, the metal resilient elements may cause damage to the glass surface in the form of scratches and crumbled-away glass particles. During the further treatment of the tube, such damage may give rise to glass fractures while the crumbled-away particles may land in places in the tube where they can adversely influence the quality of the operation of the tube. Moreover, the resilient elements sliding over the glass wall may leave behind a track of metal particles, as a result of which the required voltage stability is not obtained, particularly in tubes in which high electric operating voltages are applied to certain electrodes. This latter problem is of importance in particular in picture display tubes and projection tubes in which voltages of 16 kV and over are quite normal. Besides display tubes and projection tubes the other problems also play an important part in camera tubes.